The present invention relates generally to rotary devices such as downhole motors.
Rotary devices, such as downhole motors, often must support both thrust and torque forces. Consequently, rotary devices typically are provided with both thrust bearings and radial bearings. These bearing assemblies, especially the thrust bearings, are subject to much wear. Lubrication for such bearing systems has increased the working life of the bearings, but there remains a need for a thrust bearing for a downhole motor that does not require lubrication to maintain function.
Entry of debris into a thrust bearing will greatly accelerate failure of the bearing members. Thus, various seals have been developed to enclose the bearing assemblies in downhole motors and other rotary devices. Yet, there continues to be a need for rotary seals that are more effective and less expensive.
In some downhole motors, as well as other rotary devices, there are multiple coaxial tubular components. Often, two adjacent tubular members are designed either to rotate together or not to rotate at all relative to the other tubular members. There is a need for a means for locking adjacent tubular members together for simultaneous rotation or to prevent rotation of one of the members. Other devices have been used for this purpose. However, a need persists for a locking device that permits axial movement but prevents rotational movement between the tubular members, and yet minimizes the stress concentrations.
In downhole motors, debris from the drilling fluid can also enter the bearing section and cause problems. Accordingly, there is a need for a debris barrier between the upper section of the motor assembly and the lower bearing section.
The rotary device of the present invention addresses these needs and offers other advantages that will be come apparent from the following description.
The present invention is directed to a rotary device comprising an outer tubular assembly comprising a first outer tubular member and an inner assembly comprising a first inner elongate member coaxially received in the first outer tubular member. One of the first inner elongate member and the first outer tubular member rotates relative to the other. The rotary device further includes a rotary seal assembly comprising an annular flexible seal member received in a circumferential sinuous groove formed in either the outer surface of the first inner elongate member or the inner surface of the first outer tubular member.
The present invention further comprises a rotary device having an outer tubular assembly comprising a first outer tubular member, wherein a longitudinal groove is provided on the inner wall of the first outer tubular member. Also included is an inner assembly comprising a first inner elongate member coaxially received in the first outer tubular member. One of the first inner elongate member and the first outer tubular member rotates relative to the other. An intermediate tubular member is coaxially positioned between the first outer tubular member and the first inner elongate member. A longitudinal groove is provided on the outer wall of the intermediate tubular member. An elongate cylindrical pin is receivable in the longitudinal groove of the intermediate tubular member and the longitudinal groove of the first outer tubular member when the respective grooves are aligned, whereby rotation of the intermediate tubular member relative to the first outer tubular member is prevented and whereby axial movement of the intermediate tubular member relative to the first outer tubular member is permitted.
Still further, the present invention includes a rotary device with an outer tubular assembly comprising a first outer tubular member and an inner assembly comprising a first inner elongate member coaxially received in the first outer tubular member. A longitudinal groove is provided on the outer wall of the first outer tubular member. One of the first inner elongate member and the first outer tubular member rotates relative to the other. An intermediate tubular member is coaxially positioned between the first outer tubular member and the first inner elongate member, and a longitudinal groove is provided on the inner wall of the intermediate tubular member. An elongate cylindrical pin is receivable in the longitudinal groove of the intermediate tubular member and the longitudinal groove of the first inner elongate member when the respective grooves are aligned, whereby rotation of the intermediate tubular member relative to the first inner elongate member is prevented and whereby axial movement of the intermediate tubular member relative to the first inner elongate member is permitted.
In yet another aspect, the present invention is directed to a downhole motor. The downhole motor includes a motor section, a connecting section and a bearing section. The motor section comprises a tubular outer assembly and a motor supported in the tubular outer assembly for creating torque. The bearing section comprises a bearing housing and a drive shaft supported for rotation within the bearing housing and operatively connected to the motor. A thrust bearing assembly is included in the bearing section. The thrust bearing assembly is adapted to transmit axial pressure between the bearing housing and the drive shaft and comprises a self-lubricating thrust washer.
Still further, the present invention is directed to another embodiment of a downhole motor. In this embodiment, the motor comprises a motor section, a connecting section and a bearing section. The motor section includes a tubular outer assembly and a motor supported in the tubular outer assembly for creating torque. The bearing section comprises a bearing housing and a drive shaft supported for rotation within the bearing housing. Also included in the bearing section is at least one thrust bearing assembly for transmitting axial pressure between the bearing housing and the drive shaft. The connecting sec tion has a connecting rod for transmitting torque from the motor to the drive shaft and a universal housing for supporting the connecting rod. In addition, the motor section, the bearing section and connecting section form a continuous fluid pathway for drilling fluid. An anti-friction sleeve is positioned coaxially between the connecting rod and the universal housing whereby debris in the drilling fluid is prevented from entering the bearing section.